Studies will be performed to further evaluate certain interventions which may limit the extent of myocardial injury resulting from acute myocardial infarction. The studies will be carried out in awake animal models using the relationships between blood flow and infarction. Additional studies will be carried out to evaluate the role that local tissue response plays in the pathophysiology of infarction. BIBLIOGRAPHIC REFERENCES: Cobb, F.R., Bache, R.J., Rivas, F., and Greenfield, J.C., Jr.: Local effects of acute cellular injury on regional myocardial blood flow. J. Clin. Invest. 57:1359, 1976. Rivas, F., Cobb, F.R., Bache, R.J., and Greenfield, J.C., Jr.: Relationship between blood flow to ischemic regions and extent of myocardial infarction. Circulation Res. 38:439, 1976.